Numerous gel compositions are known in the art. Some have proven to be a convenient and efficient vehicle or carrier for the application of various active ingredients to the skin. Such active ingredients include antiperspirants, deodorants, perfumes, sunscreens, cosmetics, emollients, insect repellants, medicaments, and the like. Products incorporating a gel composition and those made entirely from a gel composition may be in the form of a soft gel or a stick. Rubbing a soft gel or solid stick containing an effective amount of an active ingredient dissolved or dispersed therein against the skin causes transfer of the gel composition to the skin surface in a layer form, leaving the active ingredient within the layer on the desired skin surface.
For topical administration of various cosmetic and health and beauty materials to the skin, a gel composition preferably should have one or more of the following desired properties: transparency, compatibility with the active ingredient, controlled release of the active ingredient, minimization of skin irritation, and the ability to suspend organic and inorganic materials, such as color pigments, glitters, water, air, metal oxides, sunscreen active particulates, and fragrances. In sunscreen applications, it is desirable if the gel itself could act as a sunscreen active ingredient. Moreover, it should moisturize the skin and exhibit water wash-off resistance, but should not have significant syneresis. For industrial applications, a gel base may offer one or more of the following properties: suspension, moisture barrier, rheology, solvency, controlled release, wetting, self-emulsifying, etc. For example, in the paint industry the properties that are important are suspension and controlled release.
A gel composition typically is made by mixing one or more compounds to be gelled with a gelling agent. Known gelling agents include metal soaps, surfactants, homopolymers, ionic homopolymers and copolymers, fumed silica, natural derivatives of gums, waxes, clay, and so on. Common gelling agents for cosmetic oils are fatty acid soaps of lithium, calcium, sodium, aluminum, zinc, and barium. A number of homopolymers and copolymers, such as atatic ethylene-propylene copolymers, have been used to gel hydrocarbons. For example, gelled mineral oils have been available; however, gel compositions including an ester, ether, alcohol, or vegetable oil are less common. Because gel compositions including an ester, alcohol, ether, or naturally-occurring fat or oil may provide a better alternative to hydrocarbon gels, there is a need for exploring methods of making such gel compositions.